Apple Mac Pro (Early 2008) - Manual (Page 75)

Chapter 4 Problem, Meet Solution 75
If the light on the front of the display is flashing
On some Apple flat panel displays, the power light displays a series of short flashes
when an error is detected.
 If you see a repeating sequence of three short flashes, the display is detecting input in
the wrong video format. Make sure your display is compatible with your graphics
card and that you’ve installed the correct display software, if your display came with
installation software.
 If you see a sequence of two short flashes and a long flash, the display is detecting a
problem with a backlighting lamp. Contact an Apple Authorized Reseller or Apple
Authorized Service Provider.
Problems with Your Internet Connection
If you have trouble with your Internet connection, you can try the steps in this section
starting with Network Diagnostics.
To use Network Diagnostics:
1 Choose Apple () > System Preferences.
2 Click Network and then click “Assist me” at the bottom of the page.
3 Click Diagnostics to open Network Diagnostics.
4 Follow the onscreen instructions.
If Network Diagnostics can’t resolve the problem, there may be a problem with the
Internet service provider (ISP) you are trying to connect to, with an external device you
are using to connect to your ISP, or with the server you are trying to access. You can
also try the steps in the following section.